Integrated circuits typically communicate with each other using conductive transmission lines such as traces on a printed wiring board or cables. An “ideal” transmission line conducts electrical signals from one integrated circuit to another integrated circuit without distortion. In practice, perfectly ideal transmission lines do not exist. As a result, signals that are driven onto one end of a transmission line emerge with varying amounts of distortion at the other end of the transmission line.
The signal usually carries multiple bits of information or data bits. As the distortion increases and the speed of the communication increases, the distortion from a bit of data may cause an adjacent bit of data to be received incorrectly. In some high speed communication where data is transferred at multiple gigabits per second, the distortion may cause pattern jitter to be present in the signal. Pattern jitter is an accumulation of the distortion (jitter) of the data bits at the receiving end of the transmission line.
Various techniques are designed to reduce the distortion caused by imperfect transmission lines. However, as the rate of the transfer of the data gets higher designing a simple technique to deal with the distortion and to suit different lengths of different transmission lines may become difficult.